A gable is the generally triangular portion of a wall between the edges of a sloping roof. The shape of the gable and how it is detailed depends on the structural system used (which is often related to climate and availability of materials) and aesthetic concerns. Thus the type of roof enclosing the volume dictates the shape of the gable. A gable wall or gable end more commonly refers to the entire wall, including the gable and the wall below it.
A gable end is an architectural term which is used to refer to the vertically triangular wall between the sloping roofs of a gable building. The gable's shape will depend on the structural system that is in use.
A variation of the gable is a crow-stepped gable, which has a stairstep design to accomplish the sloping portion. Crow-stepped gables were used in Scotland and England as early as the seventeenth century. Examples of the crow-stepped gable can be seen at Muchalls Castle and Monboddo House, both 17th century Scottish buildings. Other early examples are found in parts of Denmark and Sweden.
Gable ends of more recent buildings are often treated in the same way as the Classic pediment form. But unlike Classical structures, which operate through trabeation, the gable ends of many buildings are actually bearing-wall structures. Thus, the detailing can be ambiguous or misleading. See: John Ruskin and The Seven Lamps of Architecture. Gable style is also used in fabric structure design, with varying degree sloped roofs, dependent on how much snowfall is expected.